zoukankan html css js c++ java

SQL Server:错误处理及事务控制

解读错误信息

Msg 547, Level 16, State 0, Line 11
The INSERT statement conflicted with the FOREIGN KEY constraint "FK_Products_Categories".
The conflict occurred in database "TSQL2012", table "Production.Categories", column 'categoryid'.

Error number

● SQL Server 错误信息的编号从1~49999

● 自定义错误信息从50001开始

● 错误编号50000是为没有错误编号的自定义信息准备的。

Severity level

SQL Server 一共26个严重级别 0~25。

● 严重级别>= 16的会记录SQL Server日志和Windows 应用程序日志

● 严重级别19~25 只能由 sysadmin觉得的成员处理

● 严重级别20~25被认为是致命错误。会中断终端连接并回滚所有打开的事务。

● 严重级别0~10只是提示信息。

State int 类型，最大值127， MS internal purposes

Error message 支持255个Unicode 字符

● SQL Server 错误信息都在 sys.messages里面

● 可以用sp_addmessage 添加自定义错误信息

RAISERROR（不会中断事务）

简单的传递信息可以使用级别0~9 。

如果你有sysadmin的角色，可以使用WITH LOG选项并设置一个严重级别>20的错误。error 发生的时候SQL Server会中断连接。

使用NOWAIT选项可以直接发送信息，而不用等大赛buffer

RAISERROR ('Error in usp_InsertCategories stored procedure', 16, 0);

-- Formatting the RAISERROR string
RAISERROR ('Error in % stored procedure', 16, 0, N'usp_InsertCategories');

-- In addition, you can use a variable: 
GO
DECLARE @message AS NVARCHAR(1000) = N'Error in % stored procedure';
RAISERROR (@message, 16, 0, N'usp_InsertCategories');

-- And you can add the formatting outside RAISERROR using the FORMATMESSAGE function:
GO
DECLARE @message AS NVARCHAR(1000) = N'Error in % stored procedure';
SELECT @message = FORMATMESSAGE (@message, N'usp_InsertCategories');
RAISERROR (@message, 16, 0);

THROW （会中断事务）

-- You can issue a simple THROW as follows:
THROW 50000, 'Error in usp_InsertCategories stored procedure', 0;

-- Because THROW does not allow formatting of the message parameter, you can use FORMATMESSAGE()
GO
DECLARE @message AS NVARCHAR(1000) = N'Error in % stored procedure';
SELECT @message = FORMATMESSAGE (@message, N'usp_InsertCategories');
THROW 50000, @message, 0;

-- RAISERROR does not normally terminate a batch:
RAISERROR ('Hi there', 16, 0);
PRINT 'RAISERROR error'; -- Prints
GO

-- However, THROW does terminate the batch:
THROW 50000, 'Hi there', 0;
PRINT 'THROW error'; -- Does not print
GO

实例

使用 @@ERROR

DECLARE @errnum AS int;
BEGIN TRAN;
SET IDENTITY_INSERT Production.Products ON;
INSERT INTO Production.Products(productid, productname, supplierid, categoryid, unitprice, discontinued)
    VALUES(1, N'Test1: Ok categoryid', 1, 1, 18.00, 0);
SET @errnum = @@ERROR; 
IF @errnum <> 0 -- Handle the error
    BEGIN 
        PRINT 'Insert into Production.Products failed with error ' + CAST(@errnum AS VARCHAR);
    END

DECLARE @errnum AS int;
BEGIN TRAN;
    SET IDENTITY_INSERT Production.Products ON;
    -- Insert #1 will fail because of duplicate primary key
    INSERT INTO Production.Products(productid, productname, supplierid, categoryid,     unitprice, discontinued)
        VALUES(1, N'Test1: Ok categoryid', 1, 1, 18.00, 0);
    SET @errnum = @@ERROR;
    IF @errnum <> 0
        BEGIN 
            IF @@TRANCOUNT > 0 ROLLBACK TRAN;
            PRINT 'Insert #1 into Production.Products failed with error ' + CAST(@errnum AS VARCHAR);
        END; 
    -- Insert #2 will succeed
    INSERT INTO Production.Products(productid, productname, supplierid, categoryid,     unitprice, discontinued)
        VALUES(101, N'Test2: Bad categoryid', 1, 1, 18.00, 0);
    SET @errnum = @@ERROR;
    IF @errnum <> 0
        BEGIN 
            IF @@TRANCOUNT > 0 ROLLBACK TRAN;
            PRINT 'Insert #2 into Production.Products failed with error ' + CAST(@errnum AS VARCHAR);
        END; 
    SET IDENTITY_INSERT Production.Products OFF;
    IF @@TRANCOUNT > 0 COMMIT TRAN;
-- Remove the inserted row
DELETE FROM Production.Products WHERE productid = 101;
PRINT 'Deleted ' + CAST(@@ROWCOUNT AS VARCHAR) + ' rows';

使用 XACT_ABORT

使用XACT_ABORT，语句中发生错误，整段语句都会中止。

SET XACT_ABORT ON;
PRINT 'Before error';
SET IDENTITY_INSERT Production.Products ON;
INSERT INTO Production.Products(productid, productname, supplierid, categoryid, unitprice, discontinued)
    VALUES(1, N'Test1: Ok categoryid', 1, 1, 18.00, 0);
SET IDENTITY_INSERT Production.Products OFF;
PRINT 'After error';
GO
PRINT 'New batch';
SET XACT_ABORT OFF;

-- Using THROW with XACT_ABORT. 
USE TSQL2012;
GO
SET XACT_ABORT ON;
PRINT 'Before error';
THROW 50000, 'Error in usp_InsertCategories stored procedure', 0;
PRINT 'After error';
GO
PRINT 'New batch';
SET XACT_ABORT OFF;

@@ERROR第二个例子中使用XACT_ABORT以后，第二条语句这回就无效了。

DECLARE @errnum AS int;
SET XACT_ABORT ON; 
BEGIN TRAN;
    SET IDENTITY_INSERT Production.Products ON;
    -- Insert #1 will fail because of duplicate primary key
    INSERT INTO Production.Products(productid, productname, supplierid, categoryid,     unitprice, discontinued)
        VALUES(1, N'Test1: Ok categoryid', 1, 1, 18.00, 0);
    SET @errnum = @@ERROR;
    IF @errnum <> 0
        BEGIN 
            IF @@TRANCOUNT > 0 ROLLBACK TRAN;
            PRINT 'Error in first INSERT';
        END; 
    -- Insert #2 no longer succeeds
    INSERT INTO Production.Products(productid, productname, supplierid, categoryid,     unitprice, discontinued)
        VALUES(101, N'Test2: Bad categoryid', 1, 1, 18.00, 0);
    SET @errnum = @@ERROR;
    IF @errnum <> 0
        BEGIN 
            -- Take actions based on the error
            IF @@TRANCOUNT > 0 ROLLBACK TRAN;
            PRINT 'Error in second INSERT';
        END; 
    SET IDENTITY_INSERT Production.Products OFF;
    IF @@TRANCOUNT > 0 COMMIT TRAN;
GO
 
DELETE FROM Production.Products WHERE productid = 101;
PRINT 'Deleted ' + CAST(@@ROWCOUNT AS VARCHAR) + ' rows'; 
SET XACT_ABORT OFF;
GO
SELECT XACT_STATE(), @@TRANCOUNT;

使用TRY/CATCH

格式

--Transactions extend batches
BEGIN TRY
 BEGIN TRANSACTION 
  INSERT INTO Sales.SalesOrderHeader... --Succeeds
  INSERT INTO Sales.SalesOrderDetail... --Fails
 COMMIT TRANSACTION -- If no errors, transaction completes
END TRY
BEGIN CATCH
 --Inserted rows still exist in Sales.SalesOrderHeader SELECT ERROR_NUMBER()
 ROLLBACK TRANSACTION --Any transaction work undone
END CATCH;

BEGIN TRY
BEGIN TRAN;
    SET IDENTITY_INSERT Production.Products ON;
    INSERT INTO Production.Products(productid, productname, supplierid, categoryid, unitprice, discontinued)
        VALUES(1, N'Test1: Ok categoryid', 1, 1, 18.00, 0);
    INSERT INTO Production.Products(productid, productname, supplierid, categoryid, unitprice, discontinued)
        VALUES(101, N'Test2: Bad categoryid', 1, 10, 18.00, 0);
    SET IDENTITY_INSERT Production.Products OFF;
COMMIT TRAN;
END TRY
BEGIN CATCH
    IF ERROR_NUMBER() = 2627 -- Duplicate key violation
        BEGIN
            PRINT 'Primary Key violation';
        END
    ELSE IF ERROR_NUMBER() = 547 -- Constraint violations
        BEGIN
            PRINT 'Constraint violation';
        END
    ELSE
        BEGIN
            PRINT 'Unhandled error';
        END;
    IF @@TRANCOUNT > 0 ROLLBACK TRANSACTION;
END CATCH;

-- revise the CATCH block using variables to capture error information and re-raise the error using RAISERROR. 
USE TSQL2012;
GO
SET NOCOUNT ON;
DECLARE @error_number AS INT, @error_message AS NVARCHAR(1000), @error_severity AS INT;
BEGIN TRY
BEGIN TRAN;
    SET IDENTITY_INSERT Production.Products ON;
    INSERT INTO Production.Products(productid, productname, supplierid, categoryid,         unitprice, discontinued)
        VALUES(1, N'Test1: Ok categoryid', 1, 1, 18.00, 0);
    INSERT INTO Production.Products(productid, productname, supplierid, categoryid,         unitprice, discontinued)
        VALUES(101, N'Test2: Bad categoryid', 1, 10, 18.00, 0);
    SET IDENTITY_INSERT Production.Products OFF;
    COMMIT TRAN;
END TRY
BEGIN CATCH
    SELECT XACT_STATE() as 'XACT_STATE', @@TRANCOUNT as '@@TRANCOUNT';
    SELECT @error_number = ERROR_NUMBER(), @error_message = ERROR_MESSAGE(), @error_severity = ERROR_SEVERITY();
    RAISERROR (@error_message, @error_severity, 1);
    IF @@TRANCOUNT > 0 ROLLBACK TRANSACTION;
END CATCH;

-- use a THROW statement without parameters re-raise (re-throw) the original error message and send it back to the client. 
USE TSQL2012;
GO
BEGIN TRY
BEGIN TRAN;
    SET IDENTITY_INSERT Production.Products ON;
    INSERT INTO Production.Products(productid, productname, supplierid, categoryid,         unitprice, discontinued)
        VALUES(1, N'Test1: Ok categoryid', 1, 1, 18.00, 0);
    INSERT INTO Production.Products(productid, productname, supplierid, categoryid,         unitprice, discontinued)
        VALUES(101, N'Test2: Bad categoryid', 1, 10, 18.00, 0);
    SET IDENTITY_INSERT Production.Products OFF;
COMMIT TRAN;
END TRY
BEGIN CATCH
    SELECT XACT_STATE() as 'XACT_STATE', @@TRANCOUNT as '@@TRANCOUNT';
    IF @@TRANCOUNT > 0 ROLLBACK TRANSACTION;
    THROW;
END CATCH;
GO
SELECT XACT_STATE() as 'XACT_STATE', @@TRANCOUNT as '@@TRANCOUNT';

现实中的事务语句

删除

--删除
CREATE PROCEDURE [dbo].[Students_Delete](@ID int)
WITH EXECUTE AS CALLER
AS
BEGIN
    --Check to make sure the ID does exist
    --If not does, return error
    DECLARE @existing AS int = 0
    SELECT @existing = count(ID)  
    FROM Students
    WHERE ID = @ID
    
    IF @existing <> 1
    BEGIN
        RAISERROR ('ID does not exist', 1, 1)
        RETURN 0
    END
        --Attempt Delete
        DELETE FROM [dbo].[Students]
        WHERE ID = @ID
     
        --check to see if update occured 
        --and return status
        IF @@ROWCOUNT = 1
            BEGIN
                INSERT INTO StudentDeleteLog 
                VALUES (suser_sname(), @ID, getdate())
                RETURN 1
            END
            
        ELSE 
            RETURN 0
END
GO

更新

CREATE PROCEDURE [dbo].[Students_Update]
(    @ID int,
        @LASTNAME varchar(50),
        @FIRSTNAME varchar(50),
        @STATE varchar(50),
        @PHONE varchar(50),
        @EMAIL varchar(50),
    @GRADYEAR int,
       @GPA decimal(20,10),
    @PROGRAM varchar(50),
    @NEWSLETTER bit
)
AS
BEGIN
    --Check to make sure the ID does exist
    --If not does, return error
    DECLARE @existing AS int = 0
    SELECT @existing = count(ID)  
    FROM Students
    WHERE ID = @ID
    
    IF @existing <> 1
    BEGIN
        RAISERROR ('ID does not exist', 1, 1)
        RETURN 0
    END
    --Can not subscribe to newsletter if email is null
    IF (@email IS NULL)
        SET @NEWSLETTER = 0
 
    --Attempt Update
UPDATE [dbo].[Students]
   SET [LASTNAME] = @LASTNAME 
      ,[FIRSTNAME] = @FIRSTNAME 
      ,[STATE] = @STATE 
      ,[PHONE] = @PHONE 
      ,[EMAIL] = @EMAIL 
      ,[GRADYEAR] = @GRADYEAR 
      ,[GPA] = @GPA 
      ,[PROGRAM] = @PROGRAM 
      ,[NEWSLETTER] = @NEWSLETTER 
 WHERE ID = @ID
     
           --check to see if update occured 
           --and return status
           IF @@ROWCOUNT = 1
                RETURN 1
           ELSE 
                RETURN 0
END
GO

银行取钱

BEGIN TRAN;
    IF NOT EXISTS (
        SELECT * FROM Accounts WITH(UPDLOCK)  --只有当前的事务可以查看
        WHERE AccountID = 47387438 AND Balance >= 400
    )
    BEGIN
        ROOLBACK TRAN;
        THROW 50000,'Tobias is too poor',1;
    END
    UPDATE Accounts SET
        Balance -=400
    WHERE AccountID = 47387438;
COMMIT TRAN;

--银行取钱高效版本
BEGIN TRAN;
    UPDATE Accounts SET
        Balance -= 400
    WHERE AccountID = 47387438 AND Balance >= 400
    IF(@@ROWCOUNT <> 1)
    BEGIN
        ROLLBACK TRAN;
        THROW 50000,'Tobias is too poor ',1;
    END
COMMIT TRAN;

参考文档

Database Engine Error Severities

https://msdn.microsoft.com/en-us/library/ms164086.aspx

SET XACT_ABORT (Transact-SQL)

https://msdn.microsoft.com/zh-tw/library/ms188792.aspx

查看全文

相关阅读:
ACM ICPC 2008–2009 NEERC MSC A, B, C, G, L
POJ 1088 滑雪 DP
UVA 11584 最短回文串划分 DP
POJ 2531 Network Saboteur DFS+剪枝
 UVa 10739 String to Palindrome 字符串dp
UVa 11151 Longest Palindrome 字符串dp
UVa 10154 Weights and Measures dp 降维
 UVa 10271 Chopsticks dp
UVa 10617 Again Palindrome 字符串dp
UVa 10651 Pebble Solitaire 状态压缩 dp

原文地址：https://www.cnblogs.com/haseo/p/4380340.html